JMONAY

Apologies in advance for wordiness:

Being a fan of old Raleigh 3-speeds, I finally got a Twenty over the summer and planned to keep it mostly original but my itchy fingers and a few seriously worn parts suggested otherwise.

So far, I have given it a Biologic Joule II dynamo front wheel, Herrmans lights, new riser stem with chopped upside down drop bars, alloy Sun CR-18 rear rim, I've ground down the head tube by 1/4" to accommodate a 1" threadless upper ball bearing while retaining the quick release clamp, and I'm thinking of new cranks ...



My fork had previously been re-spaced to be wider before since it came to me with a non-original front wheel and I had to not only bend it back, but narrow the dropout spacing down to 74-ish mm to fit the Dahon wheel. I have reasons to believe I may have over-stressed the brazings in the fork crown, one being past a certain point it got significantly easier to bend. For better or for worse, I have been riding it and haven't noticed any excessive flexing so far...

Either way, I've been looking to replace the fork just for peace of mind and the only 20" fork I could find with a long-enough steerer tube was this one

I know I'll have to re-space this one too, but I'm wondering if anyone knows of others for sale (or has any they're willing to part with) that are either lugged or have suspension. The ones for sale on thorusa that fit Dahon bikes have too short of a steerer, which for a twenty, needs to be about 9 inches long.

And about the cranks, well, the original 165mm ones are slightly bent and pedal strike is a problem that I have to consciously avoid due to the height of the bottom bracket. I have a set of 140mm cottered Raleigh cranks I could fit, but would rather not go that short. I've read everything (including what Sheldon Brown has written) about fitting a new square taper spindle, and re-threading as I've done to other Raleighs but what I really am considering is welding another bottom bracket shell inside the small triangle just above the original shell to raise the height of the bb to accomodate 170mm cranks. This would also get rid of the problems associated with the width of the shell and the difficulty of re-threading a Twenty bottom bracket due to the hardness of the welds down there.

Would welding be a bad idea? i.e. would it warp the new shell or something?

Any input would be much appreciated

ApolloSoyuz1975

Re. the BB situation: Velo-Orange offers a threadless JIS-taper bottom bracket that is supposed to be compatible with any 68 mm BB shell: Grand Cru Threadless Bottom Bracket - Bottom Brackets - Components

JMONAY

I did look into that, but unfortunately my bb is 76 mm wide. I did consider having it turned down but don't really have the means to do so.

arex

If you check the UK Ebay, I think you'll find extra-long JIS spindles for use with the original Raleigh cups, long enough to work with the 76mm Twenty BB. Fair warning, though, the races didn't look very smooth to me.

arex

125mm RALEIGH CONVERTION BOTTOM BRACKET AXLE from COTTERED to COTTERLESS | eBay

JMONAY

Thanks!! If I decide that pedal strike ceases to bug me, I will go for this option. Any idea what size bearing balls are to be used? I only wonder because Sheldon brown had to mix and match, but if this implies that the original balls can be used, that would make me very happy.

rhm

On the crank, you should be able to find BMX cranks in any length you want, 165, 160, 155, whatever. They can be cheap enough that it's definitely worth trying. Frame modifications are, I think, an extreme measure. I'd stay with fairly fat tires, and your BB height should not be a problem (in my opinion). If you want skinny tires, consider going to larger wheels (451 mm rims). Don't shy away from shorter cranks; it is easy to get used to them (only drawback is, once you get to like them, you won't want to go back to long ones; this has happened to me).

For the fork, an inelegant but workable solution is an extender for the steerer tube. Cheap item, costs a few dollars, and allows you to use just about any fork. Then you can fit a threadless headset and stem. The drawbacks are a little extra weight, and you can't remove the stem extender unless you destroy the star nut first.

JMONAY

Thanks for the input! I guess I could have been more clear - I was initially considering keeping the cottered crank, which I only have the 140 and 165 mm versions. But now that I've decided to go with the square taper spindle that arex suggested, I'm just gonna use a spare set of cranks I have lying around. I was aware that welding would have been an extremely extreme measure, but in my eyes it solved the biggest problems I had. However, it would have required (probably) more effort than it was worth. Not to mention it would have been ugly but hey, woulda been something to talk about. Larger wheels would have been a possibility had I thought of that before purchasing all new wheels I will keep that in mind, though. I will also check out stem extenders.

rhm

I have a 6" cottered crank, nothing special, I think it has a 40t ring swaged on. Happy to pass it on to you if you want it.

arex

I do not. I used 6mm on my Raleigh Sports, but that's not the same width of BB, 71mm vs. 76mm. Best I can offer is follow Sheldon's advice, try the 1/4" balls first, then try 6mm, making sure the balls are tracking where they're supposed to.

Prowler 

I'll confess that this advice leaves question marks floating around my head. Please explain the logistics of how to do this check. I was puzzled when I read Sheldon's article and again here. I assume you mean out on the bench. Can I also assume that if the balls are not 'tracking where they're supposed to" that things are way off, not off a little bit. Maybe the spindle is sitting way to far out of the cup? Or way too deep?

I sort of did this lately while sizing a spindle. Put the assembly together dry on the bench (caged bearings) and measured to confirm the cup collars came to 68mm +/-. Close enough that I knew it would work in the BB and adjust correctly.

How do you check for the right bearings?

JMONAY

To the best of my knowledge, I think this means that in addition to what you said, you just have to hold the balls up to the cups and spindle to make sure they're riding on the worn spot, as opposed to opposite corners of the race on the spindle (in which case it would be too big). I think you're correct in that for it to not work, the error would have to be fairly large.

JMONAY

Thanks, that gives a good ballpark. I do happen to have some 1/4" balls lying around to experiment on first. I also have another set of Raleigh balls if they end up being suitable (the originals in my twenty feel rough but i have yet to check).

JMONAY

Aw man. so I've already bought a square taper spindle for the Twenty, but I think I still want it. Are you certain this is one that fits English bottom brackets or is there a chance it's a French one? When I was looking on ebay last month, the only 40T ones I could find were french. Do you have any photos of it?

rhm

Could you pm me your email address, please, and I'll send a couple photos and dimensions.

rhm

Correction: this crank has a 36t ring. Spindle diameter appears to be 5/8" (16 mm?) and cotter hole measures 3/8" (9.5 mm), and arm length is 6" (152 mm) so English standard. Condition is good, chrome is good, but this is not a classy crank. I see no markings at all. Condition is good, chrome is good.

JMONAY

Oh good. Will message you

arex

Something I just thought of, is that if these are indeed MADE for converting Raleighs, and not simply an aftermarket MTB spindle, 1/4" balls should work. There's still a buttload of Twentys in England, so there's a market for conversion parts.

However, if this IS an aftermarket Shimano-compatible MTB spindle, you'll most likely wind up using 6mm balls. I used a Shimano spindle w/6mm balls on my Sports, and it worked great.

Also, there's a possibility that you'll have to grind a mm or two off the inside edge of the cups, to allow them to be able to be screwed in far enough to properly seat the bearings. This is a problem you might have with either sort of spindle.

...your mileage may vary.

JMONAY

That makes sense. Thanks for the pointers!!

JMONAY

So, after this conversation, work stopped because school hit me hard and winter came so I didn't want to destroy the bike with road salt. Priorities, I guess.

Anyway, I completed it yesterday, buying the fork that I linked in the first post. I couldn't re-space it, so instead installed a longer axle with added nuts. Thank you @rhm for the cranks - they are perfect when matched with the 13t cog I had. Also, @arex - I did buy the spindle you suggested and smoothed out the races, but ended up using it on a '69 Sports. I re-used the old balls and I think the adjustable cup sticks out maybe 0.5 or 1 mm further than it did before so spacing was a non-issue. Thank you for that suggestion.

As for my Twenty, here it is.

The old bent cranks will go on the wall once they're clean.

Thank you all for your input!

noglider 

Really good work.

A few inconsequential comments:

I have a stalled Twenty project, too. I find the brakes to be unacceptable even with aluminum rims and Kool Stop brake pads. I replaced my front hub with a drum brake hub. The rear is still lousy, but I don't mind, as I don't rely on rear brakes.

@rhm says that the Twenty is mis-designed with too much fork rake and advised me to tweak mine back a bit. I did, but probably not enough. You're lucky your fork is not very raked.

Your brake cable routing is the same as is on John S Allen's Twenty, and I used the trick on my first Twenty (now long gone).

When you ground down the head tube, how did you get it precise? You don't mention the use of any machining tool. I'm going to do the same to my head tube.

The picture of the headlight doesn't seem to be of your work on it. It looks like a yellowed and nearly opaque lens. Explain?

You might find that 30 or 40 psi suffices on tires that wide.

JMONAY

Thanks!

Your Twenty with the drum brake - is this the same one that you mentioned when I was building up the drum brake Raleigh Sports two years ago? As for the Sports ('79 superbe), I feel you deserve to know what happened to it since I'm not sure if I posted about it after the project was complete. So after one year (1000 miles) of riding it like that, I decided to return it back to its original configuration and discovered that it felt much more natural and for whatever reason, a lot faster even with the same gear ratio. I've put a ton more miles on it since then and have decided to keep it as long as possible ("forever").

I also find the Twenty brakes to be very underwhelming with alloy rims, but it didn't strike me as being worse than a regular steel rim Sports which is what I usually ride. I did consider a front dynamo drum brake but did not want to disassemble the wheel set I previously built for the Superbe. I decided to keep my hopes up and wait for SA or SRAM to make 3-speed kickback coaster brake hub some day. I'm not sure if or when that will happen but for now, I'm not complaining too much about the brakes ...

... My bigger problem at the moment is the shifter. There's no real good way to mount it and route the cable at the moment. The way it is right now on the flat of the handlebar, it's hard to get out of first gear. I've considered mounting it on the stem, too. Also thought about a twist grip shifter on the stem, but the SA twist grips require much more force to operate than a Shimano twist grip so I wouldn't want to accidentally swerve into traffic when sprinting away from a traffic light I wonder if I can find one of those antler-like attachments that people put on mountain bike handlebars and go from there. Might have to chop another drop bar, too. We'll see

I suppose I should have written in the article how I ground the head tube down. I wrapped a piece of tape around it and measured a few more times just to make sure it was as exact as I could get it. I just used an angle grinder to do the bulk of the work and finished it with a Dremel and then a hand file. Not the most precise method there is but it was the best I had on hand. Seems to work just fine, as far as I can tell. Come to think of it, along with the photos of the inside of the headlight, I've also lost the photos that illustrate this process. I always take process photos and "never" lose files, and my computer is always backed up. No idea what happened here. And for what reason do you want to shorten the head tube? Just curious. Same as what I was initially trying to do?

Regarding the headlight, you are correct that I didn't do any work to the exterior - the plastic lens is super thick and indeed quite foggy. The Herrmans light is more than bright enough to overcome the lens, luckily, but of course it's no longer as bright as I would like. I had a bad experience once when my friend tried to clear up a similarly-clouded, but thinner, lens on the headlight of my 1958 Sports (thankfully I got it at least back to what it was before). Therefore, I figured I wouldn't touch the lens just yet because it seems the "fog" isn't just on the surface. I could be wrong, though. Do you have any suggestions for what I could do about the foggy lens, aside from finding a replacement?

And yes, I have been lowering the tire pressures to find out what works for me. The Marathons have much less rolling resistance than the cheap tires I had before so that's a plus.

noglider 

Yes, I'm shortening the head tube because I'm installing a threadless 1" headset.

The original gearing on the Twenty feels right to me, the only 3-speed that feels that way to me.

I don't know what you can do about the headlight. Maybe you can use the headlight buffing kit you can get at an auto-parts store. I used one on my wife's Honda Civic. It took me an hour and a half to do the job, but the results were good. It uses an abrasive and a buffer.

JMONAY

I agree about the gearing. 46/16 felt perfect for me in Ann Arbor, just as 46/20 or 48/21 does with a Raleigh Sports. I used the 36t crank mainly because of its arm length, and the 13t rear cog I removed from something else prior happened to correspond well enough. The gear ratio is a bit lower than it was before, but it should be better because I'm moving to Pittsburgh this Saturday.

And I will try the buffing kit - or at least a towel, some compound, and lots of time. If anything, it shouldn't hurt. Thanks for the suggestion, as well as the time estimate. Being the impatient person that I am, I probably would not have worked at it long enough to see good results if not for that.

Bicycle Addict

As far as the bottom bracket goes, I re tapped the threads(carefully) on mine and installed a Shimano BB55 sealed BB and can now run any crank, some think of it as brutal, but done carefully it works, this is the second I have done, the other for a mate who got some pretty good miles out of the bike before it got run over!

SixtyFivers build has some good tricks headset wise.